nOPV2 development as a global effort for polio outbreak response – Authors’ reply
Authors: Tolbert G Nyenswah, Jessica L Schue
Journal: The Lancet Global Health (2023)

We would like to express our gratitude to Ananda Bandyopadhyay and Simona Zipursky for taking the time to read and respond to our Comment1Nyenswah TG Schue JL Halting vaccine-derived poliovirus circulation: the novel type 2 oral vaccine might not be enough.Lancet Glob Health. 2023; 11: e811-e812Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar on the results presented by Stephen Kennedy and colleagues.2Kennedy SB Macklin GR Mason Ross G et al.Poliovirus antibodies following two rounds of campaigns with a type 2 novel oral poliovirus vaccine in Liberia: a clustered, population-based seroprevalence survey.Lancet Glob Health. 2023; 11: e917-e923Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar At the time of our publication, we were unable to find the status of The Gambian phase 3 study, whereas the other countries' trials were readily available on ClinicalTrials.gov with a simple search. Registering trials at ClinicalTrials.gov is not required in all instances, but it provides an excellent way to share the same information about ongoing trials that Bandyopadhyay and Zipurshky described in their response. The reference we found to The Gambian study was from an earlier Personal View from Bandyopadhyay and Zipurshky published in The Lancet Infectious Diseases.3Bandyopadhyay AS Zipursky S A novel tool to eradicate an ancient scourge: the novel oral polio vaccine type 2 story.Lancet Infect Dis. 2023; 23: e67-e71Summary Full Text Full Text PDF PubMed Scopus (12) Google Scholar The more recent article, which the authors cited in their response, was in press while our Comment was submitted to the journal.4Macklin GR Peak C Eisenhawer M et al.Enabling accelerated vaccine roll-out for Public Health Emergencies of International Concern (PHEICs): novel oral polio vaccine type 2 (nOPV2) experience.Vaccine. 2023; 41: A122-A127Crossref PubMed Scopus (21) Google Scholar This latest article, and the entire supplement it was published in, provides a timely overview on the status of vaccine-derived poliovirus type 2. Bandyopadhyay and Zipurshky's explanation on the clinical development plan of the novel oral polio vaccine type 2 (nOPV2) is most welcome given their role of Co-chairs of the Novel OPV Working Group of the Global Polio Eradication Initiative, and we appreciate their unique insights into these decisions. Without being able to verify the status of The Gambian trial, we did not include it in our Comment. Although we do not feel that this decision led to any misinformation, we agree that a misunderstanding has occurred. This type of misunderstanding serves as a case in point of why public databases such as ClinicalTrials.gov were created. Because of the length of time between trial design, data collection, and results publication, ClinicalTrials.gov is a crucial resource for the public and fellow researchers to learn about ongoing studies. We welcome Bandyopadhyay and Zipurshky's agreement that studies on nOPV2 should consider countries with higher risk and epidemiology of circulating vaccine-derived poliovirus type 2, which was core to our Comment. Furthermore, we expand that it is operationally, epidemiologically, and logistically feasible to do clinical trials in settings with poor public health infrastructure and workforce, as shown by the phase 2 Ebola vaccine trials done in Liberia during an ongoing outbreak.5Kennedy SB Bolay F Kieh M et al.Phase 2 placebo-controlled trial of two vaccines to prevent Ebola in Liberia.N Engl J Med. 2017; 377: 1438-1447Crossref PubMed Scopus (168) Google Scholar We recognise that scientific evidence and discoveries are dynamic and evolving; thus, whenever new information rapidly emerges and data are available, scientists should update the new information for the benefit of the community. The peer-review system of scientific dissemination also has its own limitations. Other sources of information, such as public databases, can address some of these limitations. We declare no competing interests. Halting vaccine-derived poliovirus circulation: the novel type 2 oral vaccine might not be enoughPolio eradication remains elusive, and its progress has been hampered by the COVID-19 pandemic.1 Wild-type polioviruses are endemic in two countries (Afghanistan and Pakistan), but equally concerning is the ongoing spread of circulating vaccine-derived poliovirus type 2 (cVDPV2) several years after the switch to bivalent oral polio vaccine (bOPV).2 The threat of a polio outbreak is greatest for countries with weak public health systems or affected by conflict. Since the transition from trivalent to bivalent OPV in 2016, community transmission of VDPV2 has continued despite the introduction of an inactivated polio vaccine. Full-Text PDF Open AccessnOPV2 development as a global effort for polio outbreak responseWe are responding to some misinformation and misunderstanding promulgated by the Comment by Tolbert Nyenswah and Jessica Schue (June, 2023)1 on the Article by Stephen Kennedy and colleagues.2 Nyenswah and Schue state they are puzzled by the choices of Belgium, Panama, and Bangladesh for the clinical studies of the novel oral polio type 2 vaccine (nOPV2), but they do not mention the phase 3 study in The Gambia that has been noted in published reports.3 Overall, nOPV2 development included clinical trials in four WHO regions—African region, European region, region of the Americas, and South-East Asia region—in populations ranging from vaccinated adults to vaccine-naive neonates. Full-Text PDF Open Access